'There are four charactaristics which together make a person a complete hypocrite.
The taint of hypocrisy will attach to the trustee who breaks his trust,
to the speaker who tells untruths,
to the maker of promises who fails to keep them and
to the man who uses foul language when in disagreement with others.
This taint will remain unless the wrongdoer mends his ways.'
HADITH OF AL-BUKHARI AND MUSLIM
On the Authority of 'Abdullah Ibn 'Amr Ibn Al-'As